Control system for electric motors.



A. J. HALL & L. G. RILEY.

CONTROL SYSTEM FOR ELECTRIC MOTORS. APPLICATION FILED ocT.23. 1913.

Patente Nov. 14,1916.

ITNES ES:

UNITED STATES PATENT OFFICE.

ARTHUR J. HALL AND LYNN G; RILEY, OF WILKINSBURG, YENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION 01 PENNSYLVANIA.

CONTROL SYSTEM FOR ELECTRIC MOTORS.

Specification ofLetters Patent.

Patented Nov. 14, 1916.

Application filed Dotober 28, 1913. Serial N 0. 796,868.

To all whom it may concern Be it known that we, ARTHUR J. HALL, a subject of the King of Great Britain, and a resident of Wilkinsbur in the county of Allegheny and State 0 Pennsylvania, and LYNN G. RILEY, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems for Electric Motors, of which the following is a specification.

Our invention relates to control systems for electric motors, and it has special reference to systems for controlling motors that auxiliary means of controlling the motor acceleration. By employing certain of the switches respectively corresponding to full field strength and normal field strength as line switches and by connecting the customary reversing switches to the armatures rather than to the field windings, as is general practice, and by reducing the number of resistance sections we have been enabled to decrease the total number of switches necessary; and, by employing a plurality of interlocking contact members in connection with the field control switches, we have found it possible, in one instance, to employ only one train line where formerly two were used.

In the accompanying drawing, Figures 1 and 2 are diagrammatic views of the control circuits and the main circuits, respectively, of a control system embodying our invention, and Fig. 3 is a chart of well-known form, showing the se uence of operation of the main-circuit switc es.

Referring to the drawing, the system of control here shown comprises electric motors .tor 31.

.1 and 2, a plurality of independently operated control switches, a master control drum 3 that is adapted to assume a plurality of motor-accelerating positions a to g, inclusive, a control reversing switch 4, and a control resistance 5 for supplying a relatively low voltage to the control switches.

Assuming that the switch devices occupy the positions in which they are illustrated,

- if the control reversing switch 4 is moved to its forward running position and the master controller 3 is moved into position a, a circuit is established from a positive line conductor 6, through a trolley 7, a control cutout switch 8, the control resistance 5, and a conductor 9 to the negative line conductor 10.

From an intermediate tap 11 in the control resistance, a relatively low-voltagecircuit is established through a conductor 12 and control finger 13,-where the circuit divides, one path including control fingers 14 and 15, which are bridged by a contact member 16, conductor 17, reversing switch fingers 18 and 19, which are bridged by a contact member 20, conductor 21, control fingers 22 and 23, which are bridged by the forward running portion of an interlocking contact member 24 of the usual type that is disposed in the control circuit connections of the main reversing switches 25 and 26, to be operated as one member in practice, circuit being continued from the control finger 23 through conductor 27 and overload trip 28, whence a parallel circuit is established, one path including conductor 29, an interlocking contact member marked R out and the magnet coil of a switch L to a conductor 31, the other path including conductor 32, an interlocking contact member marked L out and the magnet coil of a switch 33 to the conductor 31, circuit being continued from this point through an over load trip 34 and a conductor 35 to a second intermediate tap 36 of the control resistance 5. A conductor 30 serves to connect the ends of the magnet coils of the switches L and 33 that are not connected to the conduc- It should be noted that an interlocking contact member CM is adapted to assume an in or an out position according to the corresponding position of the switch L in conformity with the wellknown electrical interlock construction, A

a second circuit is connected from the control finger 13, through contact members 37 and 38, control finger 39, conductor 40, two interlocking contact members marked, respectively, G out and P out and a magnet coil of a switch S to the conductor 31,

whence the circuit is completed as hereinbeswitch R conductor 44, switch S, a resistance that bridges a switch R the reversing switch 26, the armature winding 46 of the motor 2, the field winding 47 thereof, the switch 33, and a conductor 47 to the negative line conductor 10. The motors 1 and 2, at starting, are thus disposed in series relation with the resistances 43 and 45 and severally utilized the full field connections. 1

If the master controller 3 is moved into position b, a contact member 48, which is connected to the energizing contact member 37 engages a control finger 49, circuit being continued from this point through a conductor 50 and the magnet coil of the switch R to the conductor 31 and thus to the negative line conductor. In this way, the switch R is closed, thereby short -circuiting the re sistance 43. In position 0 of the master controller, an energized contact member 51 engages a control finger 52, and a circuit is made through a conductor 53 and the magnet coil of the resistance R to the conductor 31. The switch R is thus closed, shortcircuiting the resistance 45, whereby a straight series connection of the motors 1 and 2. across the line is obtained. Also, the interlocking contact member marked R but is excluded from its control circuit, the magnet coil of switch L being energized through conductors 32 and 30. In position d, an energized contact member 54 engages a control finger 55, circuit being continued from this point through a conductor 56, control fingers 57 and 58, which are bridged by the portion of the interlocking contact member CM that corresponds to the in position, a conductor 59 and magnet coils of switches L and 60, disposed in parallel, to the conductor 31, and thence to the negative line conductor. Immediately upon the energization of the ma et coils of switches L and 60, the interloc ing contact member marked L out is excluded from its control circuit, whereby the switches L and 33 are opened and the interlocking contact member CM is moved to its out position. The circuit of conductor 56 is thus broken, but the magnet coils of switches L and 60 remain energized by means of a connection i from the conductor 27, through a conductor 61, an interlocking contact member marked R in, a conductor 62, and control fingers 63 and 58, which are bridged by a portion of the interlocking contact member CM that corresponds to the out position, to the magnet coils of the switches L and 60. In this position of the master controller, the main circuit switches L and 60 are closed, and the main switches L and 33 are opened, whereby the normal field connections are secured on the motor and a higher speed is obtained, as will be understood.

It should be noted that, by reason of the open condition of the switch R at starting, the interlocking contact niember marked R in is excluded from circuit, whereby the magnet coils of the switches L and 60 are prevented from being energized in position a, as they otherwise would be through the interlocking contact member CM. In

this way, it is rendered impossible to start the motors with normal field connection, which, as is Well understood, is undesirable for starting purposes.

During'the transition from position (1 to position 6, the contact members'51 and 54 disengage their respective control fingers .whereby the switch R is opened. A path for current to traverse themagnet coils of switches L and '33 is thus provided through the interlocking contact member marked R out and the bridging conductor 30. Upon the closure of the switches L and 33 the interlocking contact member CM is moved-to its in position, whereby the switches L and 60 are opened, since the controlcircuits therefor are opened both at the interlocking contact member CM and at the drum contact member 54. Just before the master controller reaches the position e, a contact member 64 engages a control finger 65, circuit being continued from this point through conductor 66 and a magnet coil of a switch G to the conductor 31. The magnet coil of a switch P, in parallel with the coil of switch G, is not energized by reason of the exclusion from its circuit of 'an interlocking member marked S out. In position 6, the magnet coil of switch S is deenergized by reason of the closure of the switch G and the consequent exclusion of the Y interlocking member marked G out from the circuit of the magnet coil switch S. The magnet coil of switch P is thereupon energized by reason of the inclusion in its circuit of the interlocking contact member marked S out. In the main circuit, switches L R, G, P and 33 are closed, whereby the motors 1 and 2 are disposedin parallel relation with full field connections restored, the resistance 45 being included inthe circuit of the motor 2. In position f, an energized contact member 67 engages the control finger 52, whereby the switch R is closed and the resistance 45 is short-circuited, as already explained. In position g, a contact member 68 engages the control finger 55. A circuit is thus completed through the interlocking contact member CM and the magnet coils of the switches L and 60, whereupon the switches L and 33 are opened, as hereinbefore pointed out. The normal field motor connections are thereby established for the final motor-accelerating position. It thus appears that, at starting, the two motors, with full field connections, are disposed in series relation across the line, a certain resistance being included in the circuit. The resistance is gradually excluded, and then .the field windings are changed over to the normal field connection. The motors are next disposed in parallel relation, the full field connections being reestablished and a resist ance being included in circuit with one of the motors. The resistance is then eliminated, and, finally, the normal field connections are again established.

It will be understood that modifications of the arrangement of parts and of the circuit connections herein set forth may be made within the spirit and scope of our invention. Ne, therefore, desire that only such limitations shall be imposed as are indicated in the appended claims.

We claim as our invention:

1. In a control system, the combination with a supply circuit and an electric motor having an armature and a field-magndt winding connected directly to one terminal thereof, of switching means for reversing the connections of the armature circuit, an electrically-controlled switch for normally connecting one side of said supply circuit to one end of said field winding, and a second electrically-controlled switch for connecting the said side of the supply circuit to an intermediate poiiit of said field winding under predetermined conditions.

2. A control system comprising a directcurrent supply circuit, an electric motor having an armature and a field-magnet winding connected directly to the .positive terminal thereof, a reversing-switch for said armature, an electrically-controlled switch for connecting the positive side of said supply circuit to one end of said field winding during the greater portion of acceleration, and a second electrically-controlled switch for connecting the said side of the supply circuit to an. intermediate point of said field winding to eiiect further acceleration of the motor.

3. A control system comprising a directcurrent supply circuit, an electric motor having an armature and a. field-magnet winding connected directly to the positive terminal thereof, an accelerating resistance initially connected in circuit with said motor, a reversing-switch for said armature, an electrically-controlled switch for initially, and during the greater portion of acceleration, connecting the positive side of said supply circuit to one end of said field winding, means for short-circuiting said resistance to effect predetermined motor acceleration, and a second electrically-controlled switch for subsequently connecting the said side of the supply circuit to an intermediate point of said field winding to effect further motor acceleration.

4. A control system comprising a supply circuit, a. pair of electric motors adapted for series-parallel operation and severally having armatures and field windings that are respectively connected directly to noncorresponding terminals of the armatures, a pair of reversing-switches for the respective armatures, a pair of electrically-controlled switches for normally respectively connecting non-corresponding ends of the field windings to the respective sides of said supply circuit, and a second pair of electrically-controlled switches for connecting the respective sides of the supply circuit to intermediate points of the corresponding field windings, under predetermined conditions.

5. A control system comprising a directcurrent supply circuit, a pair of electric motors adapted for series-parallel operation and severally having armatures and fieldmagnet windings that are respectively connected directly to the positive and to the negative terminal of the corresponding armatures, a plurality of accelerating resistances connected in circuit with the respective motors during initial series and initial parallel relation, a pair of reversing-switches for the respective armatures, a pair of electrically-controlled switches for initially, and during the greater portion of motor acceleration, respectively connecting the positive side of said supply circuit to one end of one field winding and connecting the negative side of the supply circuit to one end of the other field winding, means for short-circuiting said resistances to effect predetermined acceleration during both series and parallel motor operation, and a second pair of electrically-controlled switches for, subsequently to said short-circuiting, connecting the respective sides of the supply circuit to intermediate points of the corresponding field windings to efiect further motor acceleration.

6. In a control system, the combination with a supply circuit and an electric motor provided with field and armature windings, of switching means for reversing the connections of the armature circuit, and a plurality of electrically operated switches for severally acting both as supply circuit switches to connect said field winding to the supply circuit and as switches for opera- .tively connecting in circuit difl'erent amounts of said field winding to vary the motor speed. g

=7. In a control system, the combination with a supply circuit, of a plurality of sets of circuit-changing switching devices, a plurality of controlling circuits therefor, a controlling switch for said circuits, and means .for closing the control circuit of the second set through said switch when the first set occupies a predetermined position and for automatically transferring said control circuit to connection with the control circuits of said first 'set when the latter occupies another position.

8. In a control system, the combination with a supply circuit and a plurality of electric motors, of a plurality of circuit-changing switches therefor including resistancevarying switches and a plurality of sets of field-changing switches, a plurality of electro-magnetic means for severally actuating said switches, a master-controller for completing the control circuits of certain of saidand opening the control circuits of the first set as the switches actuating said contact making and. breaking means respectively an interlocking contact member .movable move to their out and "5115 positions, and j with a switch of'the first of saidsets for completing the control'circuit of said second set through said controller when said first set occupies the in position and for trans-' ferring said control circuit through said first contact making and breaking means to f; 1f connection with the control circuits. of said first set when the lattermovea-tothe out position, subsequently to the actuation of said last contact making- 'and means. a 1

9.In a control system, the

with a supply circuit and a plurality of elect? tric motors severally havingarmatures;

field windings, of a plurality of sets of fieldchanging switchesfor the respective motor a plurality of actuating coils for switches, a master controller for overni'ng' the energization of-said coils un er 'prede termined conditions, and interlocking means for closing the circuit of the actuating coils of the second set through said controller when the first set occupies a predetermined position and for automatically transferring said control circuit to connection ,with the control circuit of the actuating coils of the first set upon occupation of another position thereby. 5

In testimony whereof, we have hereunto s'ubscribed our names this 17th day of October, 1913.

ARTHUR J. HALL.-

LYNN G. RILEY. Witnesses:

' HART & SiMMoNs,

B. B. Hnms. 

